<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title>常用样式</title>
		<style>
			.mydiv{
			width: 300px;
			height: 300px;
			background-color: green;
			color: red;
			margin: 0 auto;
			text-align: center;}
			.uname{
			width: 300px;
			height: 40px;
			border-radius:50px;
			border: 1px solid red;
			background-color: aliceblue;}
		</style>
	</head>
	<body>
		<h1>背景样式</h1>
			<div class="mydiv">
				天气不错！
			</div>
			<input type="text" style="background-color: red;"/>
			<h1>边框样式</h1>
		    用户名<input type="text"class="uname"/>
	</body>
</html>